{"title":"Mercury 450R 4-Stroke Outboard Engine Parts | Marine Motor Components","description":"\u003csection id=\"hero\" style=\"padding:16px;border:1px solid #e5e7eb;border-radius:8px;max-width:1100px;margin:0 auto 18px auto\"\u003e\n  \u003cp\u003eThis page is tailored for Mercury 4‑Stroke 450R outboard engines. Use it to find compatible parts and practical service information, including maintenance tips, commonly replaced items, and troubleshooting guidance. You can also browse the main Mercury collection for a wider selection. Scroll to the bottom of this page to start browsing parts for this engine, and remember that on the collection page you can use the Filter \u0026amp; Sort controls to narrow results by horsepower, year range, and part category\/section.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\" style=\"display:inline-block;margin-top:8px;padding:10px 14px;background:#0b6efd;color:#fff;text-decoration:none;border-radius:6px\"\u003eBrowse All Mercury Parts\u003c\/a\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\" style=\"max-width:1100px;margin:0 auto 18px auto\"\u003e\n  \u003ch2\u003eHow to Identify Your 450R Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eLocate the serial number plate on the starboard side of the transom bracket or swivel bracket. Record the full serial number to confirm exact parts.\u003c\/li\u003e\n    \u003cli\u003eModel descriptors often indicate shaft length (L\/XL\/XXL), rotation (standard\/counter), and mid‑section type (e.g., AMS). These details affect gearcase, mounts, and rigging parts.\u003c\/li\u003e\n    \u003cli\u003eConfirm platform: the 450R is a high‑output 4‑stroke V8 with a belt‑driven supercharger; it differs from V10 FourStroke models (350–425 hp) and earlier non‑supercharged V8s.\u003c\/li\u003e\n    \u003cli\u003eControls and rigging: most applications use Digital Throttle \u0026amp; Shift (DTS). Note joystick\/steering options when selecting rigging or propeller components.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"engine-overview\" style=\"max-width:1100px;margin:0 auto 18px auto\"\u003e\n  \u003ch2\u003eEngine Platform Overview\u003c\/h2\u003e\n  \u003ch3\u003eMercury Racing 450R (Supercharged V8 4‑Stroke)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;border:1px solid #e5e7eb\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;padding:8px;border-bottom:1px solid #e5e7eb;width:28%\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;padding:8px;border-bottom:1px solid #e5e7eb\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eSupercharged V8, EFI, 4‑stroke outboard; heavy‑duty midsection options and high‑performance gearcases available.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eCommon Models\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003e450R AMS in L\/XL\/XXL shaft lengths; standard and counter‑rotation; various gearcase options (e.g., performance‑oriented).\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eAdvantages\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eExceptional power and mid‑range torque, DTS control integration, robust cooling and charging systems for performance use.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eNotes\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eMany routine service items are 450R‑specific due to supercharging and performance calibration. Always verify by serial number, shaft length, rotation, and midsection.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"service-kits\" style=\"max-width:1100px;margin:0 auto 18px auto\"\u003e\n  \u003ch2\u003eRoutine Maintenance \u0026amp; Service Parts\u003c\/h2\u003e\n  \u003cp\u003eIntervals below are general guidelines; always follow the procedures and timings in your official Mercury service manual for the 450R and adjust for severe duty or high‑hour use.\u003c\/p\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;border:1px solid #e5e7eb\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;padding:8px;border-bottom:1px solid #e5e7eb\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left;padding:8px;border-bottom:1px solid #e5e7eb\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left;padding:8px;border-bottom:1px solid #e5e7eb\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left;padding:8px;border-bottom:1px solid #e5e7eb;width:180px\"\u003eParts Link\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eEngine oil \u0026amp; filter\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eEvery 100 hrs or annually (after 20‑hr break‑in)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eUse the specified marine 4‑stroke oil grade; shorten interval for hard use.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/oil-filters\"\u003eOil Filters\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eGear oil (lower unit)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eEvery 100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eInspect for water intrusion and metal debris; change more often for high‑speed use.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\"\u003eMercury Outboard Parts\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eSpark plugs\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eInspect 100 hrs; replace per manual\/condition\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eHigh output engines can be sensitive to plug condition and gap.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\"\u003eMercury Outboard Parts\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eFuel filter (under‑cowl \/ inline)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eEvery 100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eReplace sooner if fuel quality is suspect or after storage.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-filters-1\"\u003eFuel Filters\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eWater pump impeller \/ kit\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eInspect annually; replace 2–3 yrs (annually in sandy\/silty water)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eCritical for cooling at idle and high load; replace housing as needed.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-water-pump-repair-kits\"\u003eMercury Water Pump Repair Kits\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eAnodes (external \u0026amp; internal)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eInspect every 60–90 days; replace when 50% wasted\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eMatch anode material to water type (zinc, aluminum, magnesium).\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/anodes\"\u003eAnodes\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eThermostats \/ poppet valve\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003e2–3 years or as needed\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eReplace if overheat alarms, slow warm‑up, or unstable temps occur.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\"\u003eMercury Outboard Parts\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px\"\u003eSupercharger drive belt\u003c\/td\u003e\n        \u003ctd style=\"padding:8px\"\u003eInspect annually; replace per manual\/usage\u003c\/td\u003e\n        \u003ctd style=\"padding:8px\"\u003eCheck for glazing, cracking, or slip; belt condition affects boost and performance.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/belt\"\u003eBelt\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"common-parts\" style=\"max-width:1100px;margin:0 auto 18px auto\"\u003e\n  \u003ch2\u003eFrequently Used Parts Categories\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eRoutine Service – \u003ca href=\"https:\/\/seasierra.com\/collections\/service-maintenance-kits\"\u003eService \u0026amp; Maintenance Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eOil \u0026amp; Filters – \u003ca href=\"https:\/\/seasierra.com\/collections\/oil-filters\"\u003eOil Filters\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eCooling System – \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-water-pump-repair-kits\"\u003eMercury Water Pump Repair Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eFuel System – \u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-filters-1\"\u003eFuel Filters\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eIgnition \/ Electrical – \u003ca href=\"https:\/\/seasierra.com\/collections\/electrical-items\"\u003eElectrical Items\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eGearcase \/ Seals – \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-lower-unit-seal-kits\"\u003eMercury Lower Unit Seal Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003ePropulsion – \u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\"\u003ePropellers\u003c\/a\u003e\n\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"troubleshooting\" style=\"max-width:1100px;margin:0 auto 18px auto\"\u003e\n  \u003ch2\u003eCommon Symptoms \u0026amp; Quick Checks\u003c\/h2\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;border:1px solid #e5e7eb\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;padding:8px;border-bottom:1px solid #e5e7eb\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left;padding:8px;border-bottom:1px solid #e5e7eb\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left;padding:8px;border-bottom:1px solid #e5e7eb\"\u003eRelated Parts\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eWeak telltale or overheat alarm\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eInspect water inlets for blockage, verify hose\/muffs water supply, check thermostat operation.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eWater pump kit, thermostat(s), poppet valve, intake screens\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003ePoor acceleration or power loss\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eConfirm fresh fuel, replace\/clogged fuel filter, check spark plugs and supercharger belt condition, review prop slip\/ventilation.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eFuel filter, spark plugs, supercharger belt, propeller\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eHard starting or rough idle\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eVerify battery health\/voltage, inspect plugs, check for stale fuel and air leaks on fuel lines.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eSpark plugs, fuel filter, fuel line\/primer components\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eGearcase noise or metal in gear oil\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eCheck lube level and color, look for water intrusion, inspect prop shaft for fishing line under the seal.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f1f5f9\"\u003eLower unit seal kit, gear lube, prop shaft seals\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px\"\u003eRapid anode consumption or visible corrosion\u003c\/td\u003e\n        \u003ctd style=\"padding:8px\"\u003eConfirm correct anode material for water type, check bonding\/grounds, look for stray current at the dock.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px\"\u003eExternal\/internal anodes, bonding straps\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"faq\" style=\"max-width:1100px;margin:0 auto 18px auto\"\u003e\n  \u003ch2\u003eFAQs\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eAre 450R parts interchangeable with other Mercury V8 or V10 models?\u003c\/summary\u003e\n    \u003cp\u003eSome routine service items may look similar across families, but the 450R’s supercharged V8 platform uses many application‑specific parts. Do not assume interchangeability with non‑supercharged V8 or V10 models—verify by serial number, shaft length, rotation, and midsection type.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhen should I replace the impeller?\u003c\/summary\u003e\n    \u003cp\u003eInspect annually and replace every 2–3 years under normal conditions. In sandy\/silty or high‑heat operation, replace yearly. If you see weak telltale flow or overheat warnings, service the entire pump kit.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should I change gear oil?\u003c\/summary\u003e\n    \u003cp\u003eChange lower unit gear oil every 100 hours or annually, and sooner if you notice water contamination, metallic particles, or after hard impacts with submerged objects.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat information helps confirm part compatibility?\u003c\/summary\u003e\n    \u003cp\u003eProvide the engine serial number, shaft length (L\/XL\/XXL), rotation (std\/counter), midsection type (e.g., AMS), gearcase type, and any control\/steering options. Photos of the serial plate and the part being replaced are also helpful.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"cta\" style=\"padding:16px;border:1px solid #e5e7eb;border-radius:8px;max-width:1100px;margin:0 auto\"\u003e\n  \u003cp\u003eReady to locate parts? Browse the main Mercury collection by horsepower, year, and model to narrow down exact‑fit components for your 450R.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\" style=\"display:inline-block;margin:8px 0 10px 0;padding:10px 14px;background:#0b6efd;color:#fff;text-decoration:none;border-radius:6px\"\u003eShop Mercury Outboard Parts\u003c\/a\u003e\n  \u003cp style=\"color:#475569\"\u003eIf you’re unsure about your model, send us a photo of the nameplate and the part you need and we’ll help verify compatibility.\u003c\/p\u003e\n\u003c\/section\u003e","products":[{"product_id":"thermostat-kit-fits-mercury-mariner-verado-v6-v8-175-300hp-replaces-8m0162139-8m0137816","title":"Thermostat Kit – Fits Mercury\/Mariner Verado V6\/V8 175-300HP (Replaces 8M0162139, 8M0137816)","description":"\u003csection\u003e\n\u003c!-- 🔧 Table Styles (include only once per page) --\u003e\n\u003cstyle\u003e\n  \/* Outer container allows horizontal scrolling (with iOS momentum) *\/\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n\n  \/* Base table styles *\/\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n\n  \/* Key: prevent wrapping, word breaks, and vertical text in headers *\/\n  table.ss-table th {\n    white-space:nowrap;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\n    font-weight:600;\n    background:#f8fafc;\n  }\n\n  \/* Small screen optimization *\/\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003eThermostat Kit – Fits Mercury Verado V6\/V8 175-300HP\u003c\/strong\u003e is essential for maintaining optimal engine temperature in Mercury and Mariner Verado 4-Stroke outboards (V6 3.4L \u0026amp; V8 4.6L, 175-300HP) manufactured from 2018 onwards (serial number 2B529482 and above).\u003c\/p\u003e\n\u003cp\u003eIt is a direct replacement for Mercury OEM part numbers 8M0162139 and its superseded predecessor, 8M0137816, ensuring a precise fit and reliable performance.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eEngineered as a direct-fit replacement for straightforward installation.\u003c\/li\u003e\n\u003cli\u003eFeatures a corrosion-resistant stainless steel housing for durability in marine environments.\u003c\/li\u003e\n\u003cli\u003eIncorporates a self-cleaning design to flush contaminants and maintain thermal efficiency.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003ePart Number\u003c\/th\u003e\n        \u003cth\u003eSuperseded By\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e8M0137816\u003c\/td\u003e\n        \u003ctd\u003e8M0162139\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n\u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n\u003cp\u003eFor Mercury and Mariner models, this part fits specific V6 and V8 Verado, Pro XS, SeaPro, and Racing engines from 2018 to the present. Always verify your engine's serial number against the ranges provided.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine \u0026amp; Model Compatibility\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003eModel\u003c\/th\u003e\n        \u003cth\u003eRated HP\u003c\/th\u003e\n        \u003cth\u003eStroke\u003c\/th\u003e\n        \u003cth\u003eYears\u003c\/th\u003e\n        \u003cth\u003eOEM Part No.\u003c\/th\u003e\n        \u003cth\u003eNotes\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 3.4L V6\u003c\/td\u003e\n\u003ctd\u003e175\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 3.4L V6 Pro XS\u003c\/td\u003e\n\u003ctd\u003e175\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 3.4L V6\u003c\/td\u003e\n\u003ctd\u003e200\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 3.4L V6 SeaPro\u003c\/td\u003e\n\u003ctd\u003e200\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8 Pro XS\u003c\/td\u003e\n\u003ctd\u003e200\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eAPEX\u003c\/td\u003e\n\u003ctd\u003e200\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2023–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 1E054353 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 3.4L V6\u003c\/td\u003e\n\u003ctd\u003e225\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8 Pro XS\u003c\/td\u003e\n\u003ctd\u003e225\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8 SeaPro\u003c\/td\u003e\n\u003ctd\u003e225\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8\u003c\/td\u003e\n\u003ctd\u003e250\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8 Pro XS\u003c\/td\u003e\n\u003ctd\u003e250\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8 SeaPro\u003c\/td\u003e\n\u003ctd\u003e250\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8 Verado\u003c\/td\u003e\n\u003ctd\u003e250\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e4.6L V8 Racing\u003c\/td\u003e\n\u003ctd\u003e250R\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2021–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 1E080500 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8\u003c\/td\u003e\n\u003ctd\u003e300\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8 Pro XS\u003c\/td\u003e\n\u003ctd\u003e300\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8 SeaPro\u003c\/td\u003e\n\u003ctd\u003e300\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8 Verado\u003c\/td\u003e\n\u003ctd\u003e300\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eVerado 4.6L V8 Verado SeaPro\u003c\/td\u003e\n\u003ctd\u003e300\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2018–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 2B529482 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e4.6L V8 Racing\u003c\/td\u003e\n\u003ctd\u003e300R\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2021–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 1E080500 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e4.6L V8 AMS Racing\u003c\/td\u003e\n\u003ctd\u003e300R\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2021–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 1E081459 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eAPEX\u003c\/td\u003e\n\u003ctd\u003e360\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2023–Present\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 1E054247 and above\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003eRacing\u003c\/td\u003e\n\u003ctd\u003e450R\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e2020–2023\u003c\/td\u003e\n\u003ctd\u003e8M0162139\u003c\/td\u003e\n\u003ctd\u003eS\/N: 1E083006-1E099720\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eThermostat\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect replacement\u003c\/dd\u003e\n  \u003cdt\u003eHousing Material\u003c\/dt\u003e\n\u003cdd\u003eCorrosion-resistant stainless steel\u003c\/dd\u003e\n  \u003cdt\u003eTemperature Rating\u003c\/dt\u003e\n\u003cdd\u003e140°F (60°C)\u003c\/dd\u003e\n  \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eSelf-cleaning design allows cooling system contaminants to flush through closing surfaces\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1 x Thermostat (8M0162139)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eEnsure the engine is completely cool and disconnect the battery for safety.\u003c\/li\u003e\n  \u003cli\u003eLocate the thermostat housing on the engine. Place a drain pan underneath to catch any residual coolant.\u003c\/li\u003e\n  \u003cli\u003eCarefully remove the housing bolts and cover. Note the orientation of the old thermostat before removing it.\u003c\/li\u003e\n  \u003cli\u003eClean the mating surfaces of the housing and cover, removing any old gasket material or sealant residue.\u003c\/li\u003e\n  \u003cli\u003eInstall the new thermostat, ensuring it is seated in the correct orientation.\u003c\/li\u003e\n  \u003cli\u003eReinstall the cover, using a new gasket if applicable, and tighten the bolts to the manufacturer's specified torque.\u003c\/li\u003e\n  \u003cli\u003eRefill the cooling system with the recommended coolant and check for leaks.\u003c\/li\u003e\n  \u003cli\u003eReconnect the battery, start the engine, and allow it to reach operating temperature, verifying that the thermostat opens correctly.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I know if my Verado's thermostat is failing?\u003c\/summary\u003e\n  \u003cp\u003eCommon signs of a faulty thermostat include engine overheating at low speeds, running too cool at cruising speeds (stuck open), or erratic temperature gauge readings. A stuck-closed thermostat will cause rapid overheating, while a stuck-open one will prevent the engine from reaching its ideal operating temperature, leading to poor fuel economy and increased engine wear.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat happens if I use a thermostat with the wrong temperature rating?\u003c\/summary\u003e\n  \u003cp\u003eUsing a thermostat with a rating different from the OEM 140°F (60°C) can harm your engine. A higher-rated thermostat can lead to overheating, while a lower-rated one can cause the engine to run too cool, impairing combustion efficiency and promoting carbon buildup.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eDoes this thermostat fit both V6 and V8 Verado models?\u003c\/summary\u003e\n  \u003cp\u003eYes, this part is designed for the newer generation of Mercury Verado engines, covering both the 3.4L V6 and 4.6L V8 platforms from 2018 to present, as detailed in the compatibility table. Always confirm your engine's serial number falls within the specified range.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow does the \"self-cleaning\" feature work?\u003c\/summary\u003e\n  \u003cp\u003eThe thermostat is engineered to allow small amounts of water and contaminants to pass through even when closed. This constant micro-flushing helps prevent sediment and salt buildup on the closing surfaces, ensuring the thermostat opens and closes reliably throughout its service life.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should I replace my engine's thermostat?\u003c\/summary\u003e\n  \u003cp\u003eWhile there is no fixed replacement interval, it is considered a preventative maintenance item. Many technicians recommend replacing thermostats every 2-3 years, especially in saltwater environments, or whenever the water pump impeller is serviced to ensure cooling system reliability.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\n  \u003cp\u003eThis listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eShipping speed \u0026amp; cost\u003c\/summary\u003e\n  \u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWarranty \u0026amp; returns\u003c\/summary\u003e\n  \u003cp\u003eCovered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused \u0026amp; in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify images\/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement, not an OEM component.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePro-Grade Standards\u003c\/strong\u003e — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723788423483,"sku":"21TH011","price":33.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/8M0137816_6_cd9acceb-fd21-4521-aa39-3b88aa65e212.jpg?v=1763031785"}],"url":"https:\/\/seasierra.com\/collections\/mercury-450r-4-stroke-outboard-engine-parts-marine-motor-components.oembed","provider":"SeaSierra","version":"1.0","type":"link"}